Process of recovering constituents of value from alkaline deposits.



ED. sTAtrES PA T OFFICE LOUIS C. JONES AND FRED L. GROVER OF SYRACUSE. NEW YURK. ASSIGNORS TO THE SOLVAY rRocEss COMPANY, YORK.

PROCESS OF RECOVERTNG CONSTITUEN' IS OF VALUE FROM ALKALINE DEPOSITS. v

or soLvAY, NEW YORK,- A CORPORATION or New,

No thawing.

ya all whom it may concern:

lie it known thatave, Loris (3. doses and Faun L. (luovnu, citizens oi the United States. residim at S mouse. in the count-v of Onondaga and State of New York. have invented a new and Improved -lrocess ot' Recovering Constituents of Value from lkaline Deposits; of which the 'following is a specification.

Our invention relates particularly to the recovery of constituents of value from deposits such as the brine of Searles Lake in "('alifornia which contains sodium carbonate, sodium sulfate aml sodium chlorid. hesides sults ot potassium amt borax.

In ail-application filed by us of even date herewith we have described a simple but efficient process for recovering potassium chlorid from such deposits in which the brine is initially .com'ent'rated at a high temperature without previously removing its smliunrearbonate content. In that proeess, the sodium carbonate is precip tated "along with sodium sulfate and sodium chlorid' and is discarded as waste.

The object of our present invention isto retainthe advantages as to the recovery of potassium chlorid incident to heating and concentrating a solution of the, salts while containing sodium carbonate and at the a same time to recover the sodiumcarbonate content of the brine in the shape of sodium bicarbonate.

To this endwe. first carbonate the brine by passingearhon dioxid gasthrougli it in any usual'or suitable manner so as to convert the sodium carbonate content into so-- rlium bicarbonate whichprecipitates and is filtered out. After the removal ot'tl1e sodiam bicarbonate such quantity of sodium carbonate is added-that tllQ'SOliltlOH-Wllflll concentrated at a high temperature will be saturated therewith and the sulfate radical "will be practically eliminated; and the solution is then eo usentrated atsuch high temperature, sav (1. as a minimum, and upward as will allow ample niargint'or sub-' sequent cooling. We have found by experience that the best results are obtained with a temperature ot'irom C. to C.

By such heating and concentration two results are effected; Boric acid and less readily soluble horic acid salts, as SOdlUIIl tetrahorate, react with the sodium carbonate,

Specification of Letters ratent.

'point where the so ution is approx Patented Feb. 13, 1917.

Application filed August 30, 1916. Serial No. 117.5 l2.

present aml are col verted into sodium mctaborate which is much more soluble than potassuuu cldornl: and. second. sodium carlu)ll:ltc. smlllllll sulfate. and sodium chlorid are prccipitatml while potassiumchlorid is, I

owing to the pres ure of the sodiuln carbonate. kept in the-solution which, as the j Ilml of the operation. thesame sodium carbonate thus'being used over ando'ver iniltflillltl'lfi ul suppl ring the quantity o t that salttrequired to be present in the brine when heated. lt' desired in the first run the proliminary step of ca imitating the. brine may be omitted thus obaining the initial quan tit of sodium caibonate called to1', .frmrr the brine itself int-lead I ncous' source.

ot' fltllll illl extra J In case it is not eesircd to recover the en-I tire carlmnate content of the brine as .bic ar-j bonate we may treat a portion of each batch of brine to convelt its carbonate content into bicarbonate an l then add such treated portion to the untre lted portion. the sodium carbonate ot' .the latter, being sullicient for the purpose of our invei'ltion for the whole -v hatch. t

When the concen ration ",has reached the saturatei lwith potassium chlorid the atout. The solution is then cooled so as to precipitate mtassiu n chlorid which comesdown in a practicall v pure state, the sodium mctaborate remaini 1:! in solut'on, and is then filtered out. potassium chlorid remaining, in the mother liquor. the mother I quor is mixed with-the succcwlin; batch of brine to be treated;

Since. however. the sodium metaborate content will increase with suceessihe batches to the saturation p )llli it is necessary to in orderto recover the draw otfand treat the mother li nor from 3 time totime in any l filltll or su-it'ab e manner to removethe sodllul metaborate; when the mother liquor can be again returned to be retreated fora furl her recover hf potas- Sllllll ehlornl.

so mg is stoppedand the precipitate filtered Mano,+oogua no o co which precipitates out upon cooling. This reaction takes place readily at a temperature of from 50' to C. The mother liquor may then be returned to the brine t'or retreatment or it may be treated directly by heating and concentration until saturated with potassium chlorid and then cooling. as inthe first instance, to recover a second crop of potassium chlorid. at'ter which it should be returned to the brine From the foregoing it will be seen that by means of our invention we not only conserve the sodium carbonate content of the brine but also realize the advantage of recovering its potassium content in a pure state and by a simple and economical procedure.

What we claim'as new and desire to se-' !cure by Letters Patent is:

1. The process of recovering constituents (of value from alkaline brines containing lsodium carbonate and potassium Salts which iconsists in arbonating the brine to convert sodium carbonate into sodium bicarbonate and precipitating. and removing the bicarbonate, adding to the solution sodium carbonate in such quantity as to prevent upon concentration the'precipitation of potassium salts until the solution is'saturated with potassium chlorid, concentrating the solution at a high temperature so as to convert boric acid and less soluble boric acid salts into more soluble sodium metaboratc and precipitate sodium carbonate, sodium chlorid,'and sodium sulfate and leave the potas'sium salts in solution and finally cooling to precipitate potassium chlorid.

{ 2. The'process of recovering constituents of value from alkaline brines containing sodium carbonate and potassium salts which consists in carbonatingthe brine to convert sodium -arbonate into sodium bicarbonate, and removing the sodium bicarbonate, adding to the solution sodium carbonate in such quantity as to prevent upon concentration the precipitation of potassium salts until the solution is saturated with potassium chlorid, concentrating the solution at a high temperature so as to precipitate sodium carbonate, sodium chlorid, and sodium sulfate while leaving sodium metaborate and potassium chlorid in solution and finally cooling the solution to precipitate potassium chlorid.

3. The process of recovering constituents of value from alkaline brines containing sodium carbonate and potassium salts whichconsists in carbonating the brine to convert sodium carbonate into sodium bicarbonate and removing the sodium bicarbonate, adding to the solution sodium carbonate in such quantity as to prevent, upon concentration. the precipitation of potassium salts until the solution is saturated with potassium chlorid, concentrating the solution at a high temperature so as to precipitate sodium carbonate, sodium chlorid and sodium sulfate and. in the succeeding repetitions of the process, adding the sodium carbonate thus precipitated to the solution after the removal of the sodium bicarbonate.

4. The process of recovering constituents of value from alkaline brines containing sodium carbonate and potassium salts which consists'in carbonating a portion-of each batch of brine-to convert its sodium carbonate content into sodium bicarbonate and re-' moving the bicarbonate, adding the treated portion of the batch to the untreated portion and then concentrating at a high temperature so as to precipitate sodium carbonate,

sodium chlorid and sodium sulfate while,

leaving potassium chlorid in solution and 'finally cooling to precipitate potassium 

